Materials Handbook 15th 2010 Part 3 ppsx

Crystalline calcium is also used in the form of a very reactive free-flowing powder of 94 to 97% purityand containing 2.5% of calcium oxide with small amounts of magne-sium and other imp

brushes The taper of the bristle gives the brush stiffness at the baseand resiliency toward the end Quality varies according to the type ofanimal, climate, and feeding The colors are white, yellow, gray, andblack They are graded by locality, color, and length; and in normaltimes the name of the place at which they are graded, such asTsingtao, Hankow, and Chungking, is an indication of the grade Thebest fibers are more than 3 in (7.6 cm) in length The Chinese nat-ural black bristles are sometimes sold at a premium The U.S bris-tles from Chester hogs are light in color and of high quality Bristlesfrom the Duroc hog are bronze in color, stiff, and superior to mostChinese grades Those from the Poland China hogs are black and

stiff, but they have a crooked flag and are of poor quality Artificial

bristles are made from various plastics, the nylon bristles being of

high quality and much used Exton, of Du Pont, was one of the nal nylon monofilament nontapered bristles Tynex, of this company,

origi-now comes both tapered and level They are more durable than

nat-ural bristles Casein bristles are made by extruding an acid

solu-tion of casein, stretching the fiber, and insolubilizing withformaldehyde or other chemicals They have good paint-carryingcapacity and good wear resistance, but are dissolved by some paint

solvents Keron bristle, of Rubberset Co., is produced from the

pro-tein extracted from chicken feathers It is nearly identical in sition to natural bristle

compo-BROMINE. An elementary material, symbol Br It is a reddish-brownliquid having a boiling point of 138°F (59°C) It gives off very irritat-ing fumes and is highly corrosive It is one of four elements called

halogens, a name derived from Greek words meaning salt producer.

They are fluorine, chlorine, iodine, and bromine They are all cally active, combining with hydrogen and most metals to form

chemi-halides Bromine is less active than chlorine but more so than iodine.

It is moderately soluble in water It never occurs free in nature, and it

is obtained from natural bromide brines by oxidation and steaming,

or by electrolysis It occurs in seawater to the extent of 65 to 70 partsper million and is extracted It is marketed 99.7% minimum puritywith specific gravity not less than 3.1, but dry elemental bromine,

Br2, is marketed 99.8% pure for use as a brominating and oxidizingagent For these uses, also, bromine is available as a crystalline pow-

der as dibromodimethyl hydantoin, containing 55% bromine.

Brom 55 is this material Bromine is also used as a flame retardant

in plastics, although its use as such has been questioned due to ronmental concerns

envi-A pound of bromine is obtained from 2,000 gal (7,570 L) of seawater

It is also produced as a by-product from the brine wells of Michiganand from the production of chemicals at Searles Lake, California,

where the bromine concentration is 12 times that of seawater It isused in the manufacture of agricultural chemicals, dyes, photographicchemicals, poison gases for chemical warfare, pharmaceuticals, disin-fectants, and many chemicals It is also employed in the extraction ofgold Bromine’s major end use, as ethylene dibromide for scavenginglead antiknock compounds in gasoline, is decreasing as these environ-mentally hazardous additives are phased out.

BRONZE. The term bronze is generally applied to any copper alloy

that has as the principal alloying element a metal other than zinc ornickel Originally the term was used to identify copper-tin alloys thathad tin as the only, or principal, alloying element Some brasses arecalled bronzes because of their color, or because they contain sometin Most commercial copper-tin bronzes are now modified with zinc,lead, or other elements

The copper-tin bronzes are a rather complicated alloy system.

The alloys with up to about 10% tin have a single-phase structure.Above this percentage, a second phase, which is extremely brittle, canoccur, making plastic deformation impossible Thus high-tin bronzesare used only in cast form Tin oxide also forms in the grain bound-aries, causing decreased ductility, hot workability, and castability.Additions of small amounts of phosphorus, in the production of phos-phor bronzes, eliminate the oxide and add strength Because tin addi-tions increase strength to a greater extent than zinc, the bronzes as agroup have higher strength than brasses—from around 60,000 to105,000 lb/in2(414 to 724 MPa) in the cold-worked high-tin alloys Inaddition, fatigue strength is high

Bronzes containing more than 90% copper are reddish; below 90%the color changes to orange-yellow, which is the typical bronze color.Ductility rapidly decreases with increasing tin content Above 20% tinthe alloy rapidly becomes white and loses the characteristics ofbronze A 90% copper and 10% tin bronze has a density of 0.317 lb/in3(8,775 kg/m3); an 80–20 bronze has a density of 0.315 lb/in3 (8,719kg/m3) The 80–20 bronze melts at 1868°F (1020°C), and a 95–5bronze melts at 2480°F (1360°C)

The family of aluminum bronzes is made up of alpha-aluminum

bronzes (less than about 8% aluminum) and alpha-beta bronzes (8 to12% aluminum) plus other elements such as iron, silicon, nickel, andmanganese Because of the considerable strengthening effect of alu-minum, in the hard condition these bronzes are among the highest-strength copper alloys Tensile strength approaches 100,000 lb/in2(690 MPa) Such strengths plus outstanding corrosion resistancemake them excellent structural materials They are also used in

wear-resistance applications and for nonsparking tools Phosphor

bronzes have a tin content of 1.25 to 10% They have excellent

mechanical and cold-working properties and a low coefficient of tion, making them suitable for springs, diaphragms, bearing plates,and fasteners Their corrosion resistance is also excellent In someenvironments, such as salt water, they are superior to copper.

fric-Leaded phosphor bronzes provide improved machinability Silicon bronzes are similar to aluminum bronzes Silicon content is

usually between 1 and 4% In some, zinc or manganese is also ent Besides raising strength, the presence of silicon sharplyincreases electrical resistivity Aluminum-silicon bronze has excep-tional strength and corrosion resistance and is particularly suited tohot working

pres-Gear bronze may be any bronze used for casting gears and worm

wheels, but usually means a tin bronze of good strength deoxidizedwith phosphorus and containing some lead, to make it easy tomachine and to lower the coefficient of friction A typical gear bronzecontains 88.5% copper, 11 tin, 0.25 lead, and 0.25 phosphorus It has atensile strength of up to 40,000 lb/in2(276 MPa), elongation 10%, andBrinell hardness of 70 to 80, or up to 90 when chill-cast The density

is 0.306 lb/in3 (8,470 kg/m3) This is SAE bronze No 65 A hard

gear bronze, or hard bearing bronze, contains 84 to 86% copper,

13 to 15 tin, up to 1.5 zinc, up to 0.75 nickel, and up to 0.5 rus Hard and strong bronzes for gears are often silicon bronze ormanganese bronze

phospho-In a modified 90–10 type of bronze, the zinc is usually from 2 to 4%,and the lead up to 1% A cast bronze of this type will have a tensilestrength of about 40,000 lb/in2(276 MPa), an elongation of 15 to 25%,and a Brinell hardness of 60 to 80, those high in zinc being thestronger and more ductile, those high in lead being the weaker.Bronzes of this type are much used for general castings and are clas-

sified as composition metal in the United States In England they are called engineer’s bronze.

Architectural bronze, or art bronze, is formulated for color and

is very high in copper One foundry formula for art bronze of a red color calls for 97% copper, 2 tin, and 1 zinc For ease of casting,

dull-however, they are more likely to contain lead, and a gold bronze for

architectural castings contains 89.5% copper, 2 tin, 5.5 zinc, and

3 lead In leaded bronze, the hard copper-tin crystals aid in holdingthe lead in solution These bronzes are resistant to acids and are

grouped as valve bronze, or as bearing bronze because of the hard

crystals in a soft matrix Federal specifications for bronze give 10grades in wide variations of tin, zinc, and lead The ASTM designates

five grades of bronze casting alloys Alloy No 1 contains 85% per, 10 tin, and 5 lead; Alloy No 5 contains 70% copper, 5 tin, and 25

lead The British coinage copper is a bronze containing 95.5%

cop-per, 3 tin, and 1.5 zinc

Many of these bronzes are designated by alloy number andgrouped into several families of standard alloys There are four

principal families of wrought bronze: copper-tin-phosphorus

alloys, or phosphor bronzes (C50100 to C52400); phosphorus-lead alloys, or leaded phosphor bronzes (C53200

copper-tin-to C54800); copper-aluminum alloys, or aluminum bronzes (C60600 to C64400); and copper-silicon alloys, or silicon

bronzes (C64700 to C66100) A few, such as two manganese bronzes, are included in the copper-zinc family of copper alloys.

The aluminum bronze family is the largest, containing nearly threedozen standard compositions

Casting alloys comprise five main families:

copper-zinc-manganese alloys, or copper-zinc-manganese bronzes (C86100 to C86800); per-tin alloys, or tin bronzes (C90200 to C91700); copper-tin-lead alloys, or leaded and highly leaded tin bronzes (C92200 to C94500); copper-tin-nickel alloys, or nickel-tin bronzes (C94700 to C94900);

cop-and copper-aluminum alloys, or aluminum bronzes (C95200 to C95900) Copper-silicon bronzes are included in the C87300 to

C87900 family of copper-silicon alloys

Flat products 0.12 in (3 mm) thick of aluminum bronze C61400

have tensile yield strengths ranging from 45,000 lb/in2 (310 MPa) inthe annealed (O60) temper to 60,000 lb/in2(414 MPa) after cold work-ing to the H04, or hard, temper, with ductility decreasing from 40 to32% elongation, respectively All casting alloys can be sand-cast,many can be centrifugally cast, and some can be permanent-mold,plaster-, and investment-cast but not die-cast Among the strongest is

manganese bronze C86300, which, as cast in sand molds, provides

a minimum tensile yield strength of 60,000 lb/in2 (414 MPa) and at

least 12% elongation Some bronzes, such as nickel-bearing silicon

bronzes and aluminum bronzes, especially those containing more

than 9% aluminum, can be strengthened by age-hardening

BRONZE POWDER. Pulverized or powdered bronze made in flakeform by stamping from sheet metal It is used chiefly as a paint pig-ment and as a dusting powder for printing In making the powder, thesheets are worked into a thin foil which becomes harder under theworking and breaks into small flakes Lubricant keeps the flakesfrom sticking to one another Usually stearic acid is used, but in thedusting powder, hot water or nonsticky lacquers are used The powder

is graded in standard screens and is then polished in revolving drumswith a lubricant This gives it the property of leafing, or forming a

metallic film in the paint vehicle The leaf is also called composition

leaf, or Dutch metal leaf, when used as a substitute for gold leaf Flitters are made by reducing thin sheets to flakes, and they are not

as fine as bronze powder Alpha Bronze, a prealloyed 91% copper,

10% tin powder from Makin Metal Powders of England for metal parts, provides greater green strength and less wear and noise

powder-in bearpowder-ing applications than a premixed 90–10 composition

The compositions of bronze powder vary, and seven alloys form the

chief commercial color grades from the reddest, called pale gold,

which has 95% copper and 5 zinc, to the rich gold which has 70% per and 30 zinc Colors are also produced by heating to give oxides ofdeep red, crimson, or green-blue The powder may also be dyed in col-ors, using tannic acid as a mordant, or treated with acetic acid or cop-per acetate to produce an antique finish The color or tone of bronzepowders may also be adjusted in paints by adding a proportion of

cop-mica powder A white bronze powder is made from aluminum

bronze, and the silvery colors are obtained with aluminum powder.The bronze powder of 400 mesh used for inks is designated as extrafine The fine grade, for stencil work, is 325 mesh Medium fine, forcoated paper, has 85% of the particles passing through a 325-meshscreen and 15% retained on the screen Near mesh, for paint pigment,has 30% passing through a 325-mesh screen A 400-mesh powder has

500 million particles per gram The old name for bronze powder is

gilding powder It is also called gold powder when used in cheap

gold-colored paints, but bronze powders cannot replace gold for use inatmospheres containing sulfur, or for printing on leather where tan-

nic acid would corrode the metal Gold pigments used in plastics are

bronze powders with oxygen stabilizers

BROOMCORN. A plant of the sorghum family, Holcus sorghum,

grown in the southwest, in Illinois and Kansas, and in Argentina andHungary It is used for making brushes and brooms and for the stems

of artificial flowers The jointed stems of the dwarf variety grown insemiarid regions are 12 to 24 in (0.30 to 0.61 m) long, but the stan-dard brush corn is up to 30 in (0.76 m) long The fibers are yellowand, when dry, are coarse and hard They are easily cleaned and read-ily dyed As a brush material, they have the disadvantage of breakingeasily and are therefore unsuited for mechanical brushes for hard ser-

vice Broom root, or rice root, is similar to broomcorn and is

suit-able for mixing with it or for coarse brushes It is from a type of grass,

Epicampes macroura, of Mexico and Guatemala The fiber is from the

tough, crinkly, yellowish roots After removal of the outer bark, thedry root is treated with the fumes of burning sulfur to improve thecolor The fibers are 8 to 18 in (0.20 to 0.46 m) long In Mexico it is

called raiz de Zacaton, or Zacaton root, and its American name, rice,

is a corruption of the Spanish word for root

BRUSH FIBERS. Industrial brushes are made from a wide variety offibers, varying from the fine and soft camel’s hair to the hard, coarse,and brittle broomcorn Bristles are the most commonly used, buttampico and piassava fibers are important for polishing brushes Thevegetable fibers used for brushes are tough and stiff compared to thefiner, flexible and cohesive fibers used for twine and for fabrics Theymay, however, come from the same plant, or even from the same leaf,

as the textile fibers, but be graded out for stiffness Palmetto fiber

is from the cabbage palm tree, Sabal palmetto, of Florida

Whisk-brooms and brushes are made from the young leafstalks and stifffloor sweeps from the leaves

A fiber finer than palmetto is obtained from the twisted roots of the

scrub palmetto, S megacarpa Arenga fiber is a stiff, strong fiber

from the stems of the aren palm tree, Arenga saccharifera, of

Indonesia The finest grades resemble horsehair Kittool is a similar

strong, elastic fiber from the large leaves of the palm tree Caryota urens, of India and Sri Lanka It is very resistant and is valued for

machine brushes Gomuti fiber and Chinese coir are fibers from other species of this palm Bass, or raphia, is a coarse fiber used for

hard brushes and brooms The heavier piassava fibers are also known

as bass, but bass is from the leaves of the palm tree Raphia vinifera,

of West Africa Darwin fiber, used for brooms and scrubbing brushes

in Australia, is from the Gahnia trifida Crin is from the leaves of the

palm tree of Algeria, although the word crin originally referred to

horsehair Crin vegetal, or vegetable crin, is fiber from the leaf of

the yatay palm, Diplothemium littorale, of Corrientes Province,

Argentina Horsehair, from the manes and tails of horses, is used for

some paintbrushes

Red sable hair is used for fine-pointed and knife-edged brushes

for show-card and watercolor use It is from the tail of the

kolin-sky, Mustela siberica, of Siberia, and the pale red hair has

strength and resiliency and very fine points Russian sable hair,

used for artists’ brushes, is stronger than red sable hair, but is lesspointed and not as elastic for water painting It is from the tail of

the fitch, Putorius putorius, of central Asia, but the so-called fitch

hair used for ordinary flowing brushes is usually skunk tail hair.

It is stiffer and coarser than fitch hair Badger hair, also used for

flowing brushes, is a resilient hair with fine points and is from the

back of the badger of Turkey and southern Russia Black sable

hair, used for signwriter brushes, is not from a sable, but is the

trade name for mixtures of marten hair, bear hair, and some otherSiberian hairs

Vegetable and animal fibers are not resilient to alkalies or acidsand cannot be wetted with them The artificial fibers of plastics such

as nylon are resistant to many chemicals For hard-service cal brushes, and for resistance to strong chemicals, brush fibers are of

mechani-steel, brass, or aluminum wire Brush wire for rotary-power brushes

for metal brushing is soft- to hard-drawn steel wire usually 0.005 in(0.013 cm) in diameter Finer wire for soft rotary brushes is a soft-drawn steel wire 0.0025 in (0.006 cm) in diameter

BUFFING COMPOSITIONS. Materials used for buffing or polishingmetals, originally consisting of dolomitic lime with 18 to 25% saponifi-able grease as a bond The lime acts as the abrasive, and in somecompositions is partly replaced by other abrasives such as emeryflour, tripoli, pumice, silica, or rouge Harsher abrasives are used inthe compositions employed for the cutting-down or buffing operations.Abrasive grains are selected for combinations of hardness, toughness,and sharpness, from the soft iron oxide to the hard and sharp alu-minum oxide Buffing compositions are usually sold under trade

names for definite uses rather than by composition Metal polishes

for hand use are now usually liquids The pastes, formerly known as

Putz cream and brash polish, contained tripoli or pumice with

oxalic acid and paraffin The liquid polishes now generally containfiner abrasives such as pumicite or diatomite, in a detergent, togetherwith a solvent, and sometimes pine oil or an alkali

BUILDING SAND. Selected sand used for concrete, for mortar for layingbricks, and for plastering Early specifications called for sand grains to

be sharp, but rounded grains are now preferred because there arefewer voids in the mixture Building sand is normally taken fromdeposits within a reasonable haul of the site of building, and is notusually specified by analysis, but should be a hard silica sand that willnot dissolve Pure white sand for finish plaster is made by grindinglimestone Building sand is required to be clean, with not more than3% clay, loam, or organic matter ASTM requirements are that allgrains pass through a 0.375-in (0.95-cm) sieve, 85% through a No 4sieve, and not more than 30% through a No 50 sieve For brick mortar,all the sand should pass through a 0.25-in (0.64-cm) sieve For plaster,

not more than 6% should pass through a No 8 sieve Flooring sand

for mastic flooring is a clean sand passing through a No 3 sieve, with

7% passing through a No 100 sieve Roofing sand is a fine, white ica sand Paving sand is divided into three general classes: for con-

sil-crete pavements, for asphaltic pavements, and for grouting

The U.S Bureau of Public Roads requires that all sand for concretepavements pass through a 0.25-in (0.64-cm) sieve, 5 to 25% should be

retained on a No 10 sieve, from 50 to 90% on a No 50 sieve, and notmore than 10% should pass through a No 100 sieve Not more than3% of the weight should be matter removable by elutriation Forasphaltic pavements small amounts of organic matter are not objec-tionable in the sand All should pass through a 0.25-in (0.64-cm)sieve, 95 to 100% through a No 10 sieve, and not more than 5%

through a No 200 sieve Grouting sand should all pass through a

No 20 sieve, and not more than 5% through a No 200 sieve Chat

sand, used for concrete pavements, is a by-product of zinc and lead

mines It is screened through a 0.375-in (0.95-cm) sieve

BUILDING STONE. Any stone used for building construction may be

classified as building stone Granite and limestone are among the

most ancient of building materials and are extremely durable Twomillion limestone and granite blocks, totaling nearly 8 million longtons (8,128 million kg), were used in the pyramid of Giza, built about

2980 B.C., the granite being used for casing Availability, or a nearsupply, may determine the stone used in ordinary building, but forpublic buildings stone is transported long distances Some sand-

stones, such as the red sandstone of the Connecticut Valley, weather

badly and are likely to scale off with penetration of moisture andfrost Granite will take heavy pressures and is used for foundationtiers and columns Limestones and well-cemented sandstones areemployed extensively above the foundations Nearly half of all the

limestone used in the United States in block form is Indiana

lime-stone Marble has a low crushing strength and is usually an

architec-tural or facing stone

Crushed stone is used for making concrete, for railway ballast,

and for road making The commercial stone is quarried, crushed,and graded Much of the crushed stone used is granite, limestone,

and trap rock The last is a term used to designate basalt, gabbro,

diorite, and other dark-colored, fine-grained igneous rocks Gradedcrushed stone usually consists of only one kind of rock and is brokenwith sharp edges The sizes are from 0.25 to 2.5 in (0.64 to 6.35 cm),although larger sizes may be used for massive concrete aggregate.Screenings below 0.25 in (0.64 cm) are employed largely for paving

Granite granules for making hard terrazzo floors are marketed in

several sizes, and in pink, green, and other selected colors

Roofing granules are graded particles of crushed rock, slate, slag,

porcelain, or tile, used as surfacing on asphalt roofing and shingles.Granules have practically superseded gravel for this purpose Black

amphibole ryolite may be used, or gray basalt may be colored

artificially for granule use The suzorite rock of Quebec contains

feldspar, pyroxenite, apatite, and mica, and it is treated to remove

the mica Ceramic granules are produced from clay or shale, fired

and glazed with metallic salts They are preferred because the color

is uniform

BULK MOLDING COMPOUND. BMC is a puttylike mixture of mosetting polyester, vinyl ester or phenolic resins, additives, fillers,pigments, and/or reinforcements generally extruded into shapes forcompression, transfer, or injection molding Bulk Molding CompoundsInc makes a dozen product series compounds, including general-pur-pose, electrical, medium- and high-strength, food-contact, and corro-sion-resistant types Depending on series, specific gravity ranges from1.7 to 2.2, heat-distortion temperatures from 400 to over 500°F (204

ther-to over 260°C), water absorption from 0.06 ther-to 0.20%, mold shrinkagefrom 0 to 6 mil/in or mm/m, dielectric strength from 300 to 500 V/mil(11.8  106 to 19.7  106 V/m), arc resistance from 180 to 245 s, andflammability from HB to VO, 5V, and VO/5V Mechanical propertiesinclude a hardness of 35 to 82 Barcol, tensile strength of 4000 to 9000lb/in2 (28 to 62 MPa), compressive strength of 15,000 to 24,000 lb/in2(103 to 165 MPa), flexural strength of 8000 to 24,000 lb/in2(55 to 165MPa) and a notched impact strength of 2 to 13 ft lb/in (107 to 694J/m) Applications include electrical coil bobbins, brush holders andconnectors, dishwares, pans, trays, tubs, and housings for headlampreflectors, small appliances, auto parts, and hand-held power tools

Nu-Stone, of Industrial Dielectrics, is a BMC that looks like granite.

BURLAP. A coarse, heavy cloth made of plain-woven jute, or jutelikefibers, and used for wrapping and bagging bulky articles, for uphol-stery linings, and as a backing fabric for linoleum Finer grades areused for wall coverings The standard burlap from India is largelyfrom jute fibers, but some hibiscus fibers are used For bags andwrappings, the weave is coarse and irregular, and the color is the nat-ural tan The coarse grades such as those used for wrapping cotton

bales are sometimes called gunny in the United States, but gunny is

a general name for all burlap in Great Britain Dundee, Scotland, isthe important center of burlap manufacture outside of India, but con-siderable quantities are made from native fibers in Brazil and othercountries Burlap is woven in widths up to 144 in (3.6 m), but 36, 40,

and 50 in (0.91, 1.02, and 1.27 m) are the usual widths Hessian is

the name of a 9.5-oz (269-g), plain-woven finer burlap made to replace

an older fabric of the same name woven from coarse and heavy flaxfibers When dyed in colors, it is used for linings, wall coverings, and

upholstery Bithess was a name for Hessian fabric coated with

bitu-men, used in India to spread over soft-earth areas as a seal for a top

coating to form airplane runways Brattice cloth is a very coarse,

heavy, and tightly woven jute cloth, usually 20 oz (567 g) used for gasbreaks in coal mines; but a heavy cotton duck substituted for thesame purpose is called by the same name Most burlap for commercialbags is 8, 9, 10, and 12 oz (226, 255, 283, and 340 g), feed bags being

8 oz (226 g) and grain bags 10 oz (283 g)

BUTADIENE Also called divinyl, vinyl ethylene, erythrene, and

pyrrolylene A colorless gas of composition CH2:CH CH:CH2 used

in the production of neoprene, nylon, latex paints, and resins.Butadiene has a boiling point of 26.6°F (3°C) and a specific gravity

of 0.6272 Commercial butadiene is at least 98% pure

Butadiene is primarily obtained as an ethylene coproduct during thesteam cracking of naphtha or gas oil It is also made by oxidation dehy-

drogenation of n-butenes, the dehydrogenation of butanes, and

conver-sion of ethyl alcohol The largest use for butadiene is the production of

elastomers, such as polybutadiene, styrene-butadiene,

poly-chloroprene, and acrylonitrile-butadiene, or nitrile rubbers.

Three types of polybutadiene are available: high-cis (97%), medium-cis (92%), and low-cis (40%) The high-cis rubber is made by

polymerization with a cobalt or nickel catalyst to keep the

detrimen-tal vinyl content below 1% The medium-cis, the most popular grade, employs a titanium catalyst, and the low-cis product uses an alkyl-

lithium initiator The rubbers have less resilience and a higher heatbuildup than natural rubber, but they also give much greater wearlife, low-temperature flexibility, and increased groove-cracking resis-tance in automotive tire treads and sidewalls, and bias truck-tirebody plies Polybutadiene is almost always used in blends with otherrubbers In tire treads, the concentration is 25 to 35% by weight; the

other components include corubbers, carbon black, extending oils, and zinc stearate activator Polybutadiene is also used as a raw material for making hexamethylenediamine, the precursor for

nylon 6,6 and acrylonitrile-butadiene-styrene plastics.

BUTTER. An edible fat made from cow’s milk by curdling with ial cultures and churning The production of butter is one of the largeindustries of the Western nations, with an annual production exceed-ing 10 billion lb (4.5 billion kg), 30% of which is made in the UnitedStates Other important producers are Germany, Holland, theScandinavian countries, Australia, New Zealand, Canada, Ireland,and Argentina Butter is an important raw material in the bakeryand confectionery industries Federal regulations require that cream-ery butter be made exclusively from milk or cream, with or withoutsalt and coloring matter, and contain not less than 80% by weight of

milk fat, not over 15% moisture, and not over 2.5% salt Butter variesgreatly in color and flavor according to the feed of the animal, the pro-cessing, and the storage The natural color is whitish in winter andyellow in summer, when the animal feeds on green pasturage.Commercial butter is usually brought to a uniform yellow by coloringwith annatto Musty, garlicky, and fishy flavors may be caused bynoxious weeds eaten by the animal; cheesy or yeasty flavors may befrom stale cream; metallic, greasy, scorched, or alkaline flavors may

be from improper processing Whipped butter has 50% greater

vol-ume in the same weight and has greater plasticity for spreading.United States grades for creamery butter range from 93 score forthe best butter of fine flavor and body down to 85 score for the lowestgrade having pronounced obnoxious weed flavor and defects in body,color, or salt The grading, or scoring, of butter is done by experts Theflavor is determined by the senses of taste and smell The flavor, body,color, and salt are rated independently, and points, or scores, are sub-tracted for defects Body and texture of the butter are determined bythe character of the granules and their closeness The most commonbody defects are gumminess, sponginess, crumbliness, and stickiness.The most common defect in color is lack of uniformity, with waves ormottles Defects in salting are excessive salt and undissolved saltgrains Butter held in storage at improper temperatures is likely todevelop rancid or unpleasant flavors and acidity due to chemicalchanges, or it may absorb flavors from surrounding products High-grade butter can be held in well-regulated cold storage for long peri-ods without appreciable deterioration

An important substitute for butter is margarine Oleomargarine

is a term still retained in old food laws, but the product is no longermanufactured It was a compound of mutton fat with vegetable tallowsand fats, invented by the French chemist Mege-Mouries Margarine ismade from a mixture of about 80% vegetable oils and 20 milk in thesame manner as butter It has a slightly lower melting point than but-ter, 72 to 81°F (22 to 27°C), but the melting point and a desired degree

of saturation of the fatty acids can be regulated by hydrogenation ofthe oils Margarine of lower melting points is used in the bakery indus-try, and grades with higher melting points are for table use From 2.5

to 4% salt is used, together with vitamins A and D, lecithin, annattocoloring, and sometimes phosphatides to prevent spattering when used

for frying Biacetyl, C4H6O2, a colorless, pungent, sweet liquid whichgives the characteristic flavor to butter, is also added The food value

is, in general, higher than that of butter; but because of the tion with butter, various federal and state regulations restrict its use

competi-Soya butter is made from emulsified soybean; and when fortified with

butyric acid, the characteristic acid of butter, it is practically

guishable from butter It is, however, subject to restrictive regulations.

Butter flavors are used in confectionery and bakery products Butter-Aid is made by extracting and concentrating the esters of nat-

ural butter It is used as a high-strength flavor in foodstuffs in the

form of powder or liquid emulsion Butta-Van is a butter flavor with

vanilla It contains butyric acid, ethyl butyrate, coumarin, vanillin,

and glycerin in water solution Ghee butter, used in India, is made

from buffalo milk, sometimes mixed with cow’s milk It is clarified andthe moisture removed by boiling and slow cooling and separating offthe opaque white portion It is light in color and granular

Cheese is an important solid food product made from whole or skim

milk It contains all the food value of milk, including the proteins of

the casein The biotics used in the manufacture produce n-butyric

acid, also with caproic, caprylic, and capric acids in varying amountswhich produce the flavor of the various types of cheese In the same

manner, lipase enzymes from the glands of calves and lambs are

used for enhancing the flavor of food products containing milk or terfat The enzymes hydrolyze the butyric or other short-chained fatty

but-acids into the glycerides Lipolyzed butter, of Marschall Dairy

Laboratories, Inc., is made by treating natural butterfat withenzymes It gives intensity and uniformity of flavor to margarine andbakery products

CADMIUM. A silvery-white crystalline metal, symbol Cd It has a cific gravity of 8.6, is very ductile, and can be rolled or beaten intothin sheets It resembles tin and gives the same characteristic crywhen bent, but is harder than tin A small addition of zinc makes itvery brittle It melts at 608°F (320°C) and boils at 1409°F (765°C).Cadmium is employed as an alloying element in soft solders and infusible alloys, for hardening copper, as a white corrosion-resistantplating metal, and in its compounds for pigments and chemicals It isalso used for nickel-cadmium batteries and to shield against neutrons

spe-in atomic equipment; but gamma rays are emitted when the neutronsare absorbed, and these rays require an additional shielding of lead.The metal is marketed in small, round sticks 12 in (0.31 m) long, in

variously shaped anodes for electroplating, and as foil Cadmium

foil is 99.95% pure cadmium and is as thin as 0.0005 in (0.013 mm).

It is used for neutron shielding and for electronic applications ing high corrosion resistance Electrolytic cadmium is 99.95% pure It

requir-is obtained chiefly as a by-product of the zinc industry by treating theflue dust and fumes from the roasting of the ores Flue dust importedfrom Mexico averages 0.66 ton (600 kg) of cadmium per ton (metricton) of dust About half the world production is in the United States.Other important producers are West Germany, Belgium, Canada, and

Poland The only commercial ore of the metal is greenockite, CdS,

which contains theoretically 77.7% cadmium This mineral occurs

in yellow powdery form in the zinc ores of Missouri Cadmium occurs insphalerite to the extent of 0.1 to 1%

Most of the consumption of cadmium is for electroplating For a rosion-resistant coating for iron or steel, a cadmium plate of 0.0003 in(0.008 mm) is equal in effect to a zinc coat of 0.001 in (0.025 mm) Theplated metal has a silvery-white color with a bluish tinge, is denserthan zinc and harder than tin, but electroplated coatings are subject

cor-to hydrogen embrittlement, and aircraft parts are usually coated by

the vacuum process Cadmium plating is not normally used on

cop-per or brass since copcop-per is electronegative to it; but when these als are employed next to cadmium-plated steel, a plate of cadmiummay be used on the copper to lessen deterioration

met-Small amounts of cadmium added to copper give higher strength,hardness, and wear resistance, but decrease the electrical conductiv-

ity Copper containing 0.5 to 1.2% cadmium is called cadmium

cop-per or cadmium bronze Hitenso is a cadmium bronze of American

Brass Co It has 35% greater strength than hard-drawn copper and85% the conductivity of copper The cadmium bronze known in

England as conductivity bronze, used for electric wires, contains

0.8% cadmium and 0.6 tin Tensile strength, hard-drawn, is 85,000lb/in2 (586 MPa), and conductivity is 50% that of copper Cadmium

nitrate, Cd(NO3)2, is a white powder used for making cadmium yellow

and fluorescent pigments, and as a catalyst Cadmium sulfide CdS,

is used as a yellow pigment, and when mixed with cadmium

selenide, CdSe, a red powder, it gives a bright-orange pigment The

sulfide is used for growing cadmium sulfide crystals in plates and

rods for semiconductor uses Crystals grown at 1922°F (1050°C) arenearly transparent, but those grown at higher temperatures are darkamber Cadmium, a carcinogen, can be extremely toxic, and caution isrequired not to create dust or fumes Because of its toxicity, use in cer-tain applications—pigments, for example—has declined considerably

CAFFEINE. An alkaloid which is a white powder when it has the position C8H10N4O2 and occurs in crystalline flakes when it has onemolecule of water of crystallization The melting point is 459°F(237°C) It is soluble in chloroform and slightly soluble in water andalcohol It is the most widely used of the purine compounds, whichare found in plants Caffeine stimulates physically to lessen fatigue,but in large amounts is highly toxic Its prime use is in medicine, butmost of the production is used in soft drinks Caffeine does not nor-mally break down in the human body, but passes off in the urine, andthe effect is not cumulative; but sarcosine, which occurs in muscles, is

a decomposition product of caffeine, though it normally comes fromnitrogen metabolism Caffeine is obtained from coffee, tea waste, kolanuts, or guarana by solvent extraction, or as a by-product in the man-ufacture of noncaffeine coffees, or in the processing of coffee for theproduction of oil and cellulose It is made synthetically from

dimethyl sulfate, a volatile toxic liquid of composition

H(CH2)O(SO2)O(CH2)H, also used for making codeine and otherdrugs Synthetic caffeine is made from urea and sodium cyanoacetateand is equal chemically to natural caffeine

Less than 1% caffeine is obtained from coffee, about 2 from tea

waste, and 1.5 from kola nuts In tea it is sometimes called theine.

Cocoa waste contains theobromine, from which caffeine may be

pro-duced by adding one more methyl group to the molecular ring Thename is a deception, as there is no bromine in the molecule.Theobromine is a more powerful stimulant than caffeine It is a bitterwhite crystalline powder of composition C7H8N4O2, also called

dimethyl xanthine and used in medicine Guarana contains the

highest percentage of caffeine of all the beverage plants, about 3% It

comes from the seeds of the woody climbing plant Paullinia cupana,

of the Amazon Valley The Indians grind the seeds with water andmandioca flour and dry the molded paste with smoke For use it is

grated into hot water Kola nuts are the seeds of the fruit of the large

spreading tree Kola acuminata, native to West Africa and cultivated also in tropical America, and K nitida of West Africa The nuts of the

latter tree contain the higher percentages of theobromine and feine The white nuts are preferred to the pink or red varieties A sim-

caf-ilar product consists of caffeine and sodium benzoate Both formulations are far more soluble in water than caffeine Citrated

caffeine, used in pharmaceuticals, is a white powder produced by the

action of citric acid on caffeine, and it contains about equal quantities

by weight of anhydrous caffeine and citric acid

CAJEPUT OIL. A greenish essential oil distilled from the leaves of the

tree Melaleuca leucadendron, growing chiefly in Indonesia It

con-tains the cineole of eucalyptus oil and the terpinol which is

charac-teristic of the lilac It has a camphorlike odor It is used in medicine

as an antiseptic and counterirritant, and in perfumes Naouli oil is a

similar oil from the leaves of the tree M viridi of New Caledonia.

Cajeput bark, from the same tree, is used as an insulating material

in place of cork The bark, up to 2 in (5.08 cm) thick, is soft, light,resistant, and a good insulator

CALCITE. One of the most common and widely diffused materials,occurring in the form of limestones, marbles, chalks, calcareous

marls, and calcareous sandstones It is a calcium carbonate,

CaCO3, and the natural color is white or colorless, but it may betinted to almost any shade with impurities The specific gravity isabout 2.72 and Mohs hardness 3 Calcite is usually in compact

masses, but argonite, formed by water deposition, develops in ating flowerlike growths often twisted erratically Iceland spar, or

radi-calc spar, is the name for the perfectly crystallized, water-clear,

flaw-less calcite crystals of optical grade used for the manufacture of Nicol

prisms for polarizing microscopes, photometers, calorimeters, and

polariscopes It comes from Iceland, Spain, South Africa, and NewMexico, and some crystals have been found as large as 17 lb (7.7 kg)

The common black calcite, containing manganese oxide, often also

contains silver in proportions high enough to warrant chemicalextraction of the metal

CALCIUM. A metallic element, symbol Ca, belonging to the group ofalkaline earths It is one of the most abundant materials, occurring incombination in limestones and calcareous clays The metal isobtained 98.6% pure by electrolysis of the fused anhydrous chloride

By further subliming, it is obtained 99.5% pure Calcium metal is

yellowish white It oxidizes easily, and when heated in air, burns with

a brilliant white light It has a density of 0.056 lb/in3 (1,550 kg/m3), amelting point of 1540°F (838°C), and a boiling point of 2625°F(1440°C) Its strong affinity for oxygen and sulfur is utilized as acleanser for nonferrous alloys As a deoxidizer and desulfurizer, it isemployed in the form of lumps or sticks of calcium metal or in ferroal-loys and calcium-copper For the reduction of light-metal ores, it is

used in the form of the hydride Crystalline calcium is also used in

the form of a very reactive free-flowing powder of 94 to 97% purityand containing 2.5% of calcium oxide with small amounts of magne-sium and other impurities The specific gravity of the powder is 1.54,and the melting point is 1562°F (851°C) Natural calcium compounds,

such as dolomite, are used directly as a flux in melting iron Calcium

is also used to harden lead, and calcium silicide is used in making

some special steels to inhibit carbide formation

Many compounds of calcium are employed industrially, in ers, foodstuffs, and medicine It is an essential element in the forma-

fertiliz-tion of bones, teeth, shells, and plants Oyster shells form an

important commercial source of calcium for animal feeds They arecrushed, and the fine flour is marketed for stock feeds and the coarse

for poultry feeds The shell is calcium carbonate Edible calcium, for adding calcium to food products, is calcium lactate, a white pow-

der of composition Ca(C3H5O3)2 5H2O, derived from milk Calcium

lactobionate is a white powder that readily forms chlorides and

other double salts and is used as a suspending agent in

pharmaceuti-cals It contains 4.94% available calcium Calcium phosphate, used

in the foodstuffs industry and in medicine, is marketed in several

forms Calcium diphosphate, known as phosphate of lime, is

CaHPO4 2H2O, or in anhydrous form It is soluble in dilute citricacid solutions and is used to add calcium and phosphorus to foods,

and as a polishing agent in toothpastes Calcium monophosphate

is a stable, white, water-soluble powder, CaH4P2O8 H2O, used in

baking as a leavening agent The anhydrous monocalcium

phos-phate, CaH4(PO4)2, for use in prepared flour mixes, is a white der with each particle having a coating of a phosphate that is solubleonly with difficulty, to delay solution when liquids are added

pow-Calcium triphosphate, Ca3(PO4)2, is a white, water-insoluble der used to supply calcium and phosphorus to foods, as a polishing

pow-agent in dentifrices, and as an antacid Calcium sulfite, CaSO32H2O, is a white powder used in bleaching paper pulp and textiles,and as a disinfectant It is only slightly soluble in water, but it loses

its water of crystallization and melts at 212°F (100°C) Calcium

sili-cate, CaO SiO2, is a white powder used as a reinforcing agent inrubber, as an absorbent, to control the viscosity of liquids, and as a

filler in paints and coatings It reduces the sheen in coatings Silene

EF is a precipitated calcium silicate for rubber Micro-Cal, of

Manville Corp., is a synthetic calcium silicate with particle size assmall as 0.79
in (0.02
m) It will absorb up to 6 times its weight ofwater, and 3 lb (1.36 kg) will absorb 1 gal (0.0038 m3) of liquid andremain a free-flowing powder

Calcium metasilicate, CaO SiO3, is found in great quantities as

the mineral wollastonite near Willsboro, New York, mixed with about

15% andradite The thin, needlelike crystals are easy to crush andgrind, and the impurities are separated out The ground material is abrilliant white powder in short fibers, 99.5% passing a 325-meshscreen It is used in flat paints, for paper coatings, as a filler in plastics,for welding-rod coatings, and for electrical insulators, tile, and other

ceramics Calcium acetate, Ca(C2H3O2)2 H2O, is a white powder used

in liming rosin and for making metallic soaps and synthetic resins It is

also called lime acetate, acetate of lime, and vinegar salts.

Calcium hydroxide, Ca(OH)2, a by-product of acetylene production,

is used mainly in fertilizers and water-treating chemicals Also

referred to as carbide lime and slaked lime, it is marketed as

White Knight 100 by ReBase Products Stabilized to prevent

reac-tion with carbon dioxide in the atmosphere, the fine particles can

serve as a lightweight alternative to calcium carbonate fillers in

polyolefin and polyvinyl chloride plastics

CALCIUM CARBIDE. A hard, grayish-black, crystalline substance usedchiefly for the production of acetylene gas for welding and cuttingtorches and for lighting It was discovered in 1892 and was widelyemployed for theater stage lighting and for early automobile head-lights It is made by reducing lime with coke in the electric furnace, at

3632 to 3992°F (2000 to 2200°C) It can also be made by heatingcrushed limestone to a temperature of about 1832°F (1000°C), flowing

a high-methane natural gas through it, and then heating to 3092°F(1700°C) The composition is CaC2, and the specific gravity is 2.26 Itcontains theoretically 37.5% carbon When water is added to calcium

carbide, acetylene gas is formed, leaving a residue of slaked lime.

Pure carbide will yield 5.83 ft3(0.16 m3) of acetylene per 1 lb (0.45 kg)

of carbide, but the commercial product is usually only 85% pure.Federal specifications require not less than 4.5 ft3(0.13 m3) of gas per

l lb (0.45 kg) Although calcium carbide is principally used for makingacetylene, this market is shrinking as acetylene is recovered increas-ingly as a by-product in petrochemical plants A growing applicationfor calcium carbide is desulfurization and deoxidation of iron and

steel It is also a raw material for production of calcium cyanamide CALCIUM CHLORIDE. A white, crystalline, lumpy or flaky material ofcomposition CaCl2 The specific gravity is 2.15, the melting point is1422°F (772°C), and it is highly hygroscopic and deliquescent withrapid solubility in water The commercial product contains 75 to 80%CaCl2, with the balance chiefly water of crystallization Some is mar-keted in anhydrous form for dehydrating gases It is also sold inwater solution containing 40% calcium chloride Calcium chloride hasbeen used on roads to aid in surfacing, absorb dust, and preventcracking from freezing It is used for accelerating the setting of mor-tars, but more than 4% in concrete decreases the strength of the con-crete It is also employed as an antifreeze in fire tanks, for brinerefrigeration, for storing solar energy, as an anti-ice agent on streetpavements, as a food preservative, and in textile and paper sizes as agelling agent In petroleum production, it is used in drilling muds,cementing operations, and workover or completion fluids Calciumchloride is obtained from natural brines and dry lake beds, aftersodium chloride, bromide, and other products are extracted The

magnesium-calcium brine remaining is marketed for dust control

or purified into calcium chloride It is a by-product of sodium bicarbonateproduction via the Solvay process and is made in small quantities byneutralizing waste hydrochloric acid with lime or limestone

CALCIUM-SILICON. An alloy of calcium and silicon used as a ing agent for the elimination of sulfur in the production of steels andcast irons Steels deoxidized or treated with calcium or calcium and sil-

icon can have better machinability than those deoxidized with minum and silicon It is marketed as low-iron, containing 22 to 28%calcium, 65 to 70 silicon, and 5 maximum iron, and as high-iron, con-taining 18 to 22% calcium, 58 to 60 silicon, and 15 to 20 iron It comes

alu-in crushed form and is added to the molten steel At the temperature ofmolten steel, all the calcium passes off and leaves no residue in the

steel Calcium-manganese-silicon is another master alloy

contain-ing 17 to 19% calcium, 8 to 10 manganese, 55 to 60 silicon, and 10 iron

CAMEL’S HAIR. The fine, tough, soft hair from the mane and back of

the camel, Camelus bactrianus, used for artists’ brushes and

indus-trial stripping brushes Most of the hair is produced in central Asiaand Iran, and the grades preferred for brushes are from the crossbred

Boghdi camel The hair from the dromedary, also called djemel, or

camel, is of poor quality Much of the camel hair is not cut, but ismolted in large patches and is picked up along the camel routes Theplucked beard hair and the coarse outerguard hair obtained in comb-ing are the brush fibers They are tough, silky, and resilient The

length is 5 to 8 in (12.7 to 20.3 cm) The fine body hair, or camel

wool, which constitutes about 90% of the total fiber, is 1.5 to 2 in (3.8

to 5.1 cm) long, has a fine radiance, a pale tan color, and a downy feel

It is the textile fiber The beard hair from the Cashmere goat is verysimilar to camel hair and is used for brushes Various other hairs areused for making camel’s-hair brushes, including ox-ear hair, badgerhair, and sable hair

CAMPHOR. The white resin of Cinnamomum camphora, an evergreen

tree with laurellike leaves, reaching a height of 100 ft (30 m) The treeoccurs naturally in China and southern Japan, and is also grown inFlorida Taiwan is the center of the industry Camphor, C10H16O, has aspecific gravity of 0.986 to 0.996 and melts at 356°F (180°C) It isinsoluble in water, but soluble in alcohol or ether Camphor is used forhardening nitrocellulose plastics, but it is also used in pharmaceuti-cals, disinfectants, and explosives and chemicals It is obtained fromthe trunks, roots, and large branches by steam distillation From 20 to

40 lb (9.1 to 18.1 kg) of chips produces 1 lb (0.5 kg) of camphor Crude

camphor is pressed to obtain the flowers of camphor and camphor

oil The crude red camphor oil is fractionated into white and brown

oils; the white oil is used in soaps, polishes, varnishes, cleaners, and

pharmaceuticals; and the brown oil is used in perfumery White

cam-phor oil is a colorless liquid with a camcam-phor odor and a specific

grav-ity of 0.870 to 1.040, and it is soluble in ether or chloroform Camphor

oil may also be distilled from the twigs Camphor sassafrassy oil is

a camphor-oil fraction having a specific gravity of 0.97 It is a safras tone and is used for scenting soaps and sprays

Borneo camphor, or borneol, is a white, crystalline solid

obtained from the tree Dryobalanops camphora of Borneo and

Sumatra It is used as a substitute for camphor in cellulose plastics

It has composition C10H17OH and a specific gravity of 1.01, is soluble

in alcohol, and sublimes at 414°F (212°C) The wood of this tree,

known as Borneo camphorwood, or kapur, is used for

cabinet-work It has a density of 50 lb/ft3 (801 kg/m3), an interlocking grain,

and a scent of camphor It is also known as camphorwood.

Artificial camphor is bornyl chloride, C10H17Cl, a derivative ofthe pinene of turpentine It has a camphor odor and the same indus-trial uses as camphor, but is optically inactive and is not used in

pharmaceuticals A compound derived from natural camphor,

10-camphor-sulfonic acid, is used extensively in the optical

resolu-tion of amines Synthetic camphor, made from turpentine, in

refined form is equal to the natural product for medicinal use, andthe technical grade is used in plastics The camphor substitute

Lindol, of Hoechst Celanese Corp., is tricresyl phosphate, or tolyl phosphate, (CH3C6H4)3PO4, a colorless, odorless viscous liquidwhich solidifies at 4°F (20°C) Like camphor, it hardens cellulosenitrate and makes it nonflammable Tricresyl phosphate is also used

as an additive to gasoline to prevent buildup of carbon deposits onthe spark plugs and in the engine, thus increasing power by prevent-ing predetonation Other uses are as a plasticizer for syntheticresins, as a hydraulic fluid, and as an additive in lubricants It ismade from petroleum and from the cresylic acid from coal

Triphenyl phosphate, (C6H5)3PO4, is also used as a substitute forcamphor in cellulose nitrate and for making coating compounds non-flammable It is a colorless solid, melting at 120°F (49°C)

Dehydranone, of Union Carbide Corp., Chemicals Div., is dracetic acid, C8H8O4, a white, odorless solid with some of theproperties of camphor, used in nitrocellulose and vinyl resins

dehy-Cyclohexyl levulinate, CH3CO(CH2)2COOC6H11, is used as a stitute for camphor in nitrocellulose and in vinyl resins and chlori-nated rubber It is a liquid of specific gravity 1.025, boiling point509°F (265°C), and freezing point 94°F (70°C) Adamantane has

sub-the odor of camphor and turpentine It is obtained from sub-the crudepetroleum of Moravia as a stable, crystalline solid, melting at 514°F(268°C) It has the empirical formula C10H16, and the molecule has

four transcyclohexane rings Camphorene, C20H32, is made fromturpentine by polymerizing two myrcene molecules It is a raw mate-rial for producing geraniol and linalol

CAMWOOD. The wood of the tree Baphia nitida, native to West

Africa, used for tool handles and for machine bearings It will

stand heavy bearing pressures The wood is exceedingly hard, has acoarse, dense grain, and has a density of 65 lb/ft3 (1,041 kg/m3) It

contains a red coloring matter known as santalin and was once

val-ued as a dyewood for textiles Barwood, from the tree Pterocarpus

santalinus, of West Africa, is a similar reddish hardwood containing

the same dye and used for the same purposes

CANAIGRE. A tanning material extracted from the roots of the

low-growing plant Rumex hymenosepalus of northern Mexico and the arid

southwest of the United States The plant is known locally as sour

dock, and the roots contain up to 40% tannin The cultivated plant

yields as much as 20 tons/acre (4.8 kg/m2) of root Canaigre extract

contains 30% tannin It produces a firm, orange-colored leather.Canaigre was the tanning agent of the Aztec Indians, and is stillextensively cultivated

CANARY SEED. The seeds of the canary grass, Phalaris canariensis,

native to the Canary Islands, but now grown on a large scale inArgentina for export and in Turkey and Morocco for human food andfor export In international trade it is known by the Spanish name

alpiste It is valued as a bird food because it contains phosphates,

iron, and other minerals and is rich in carbohydrates It is, however,low in proteins and fats and is usually employed in mixtures

Birdseed is an extensive item of commerce, but the birdseed that

reaches the market in the United States is usually a blend of canaryseed and millet, with other seeds to give a balanced food Canary seed

is small, pale yellow, and convex on both sides The term Spanish

canary seed is applied to the choice seed regardless of origin Niger

seed, also valued as a birdseed, is from the plant Guizotia abyssinica,

of the thistle, or Compositae family, grown in India, Africa, Argentina,

and Europe It is also known as inga seed, rantil, kala til seed, and

black sesame It is called gingelli in India, although this name and til are more properly applied to sesame The seed is high in proteins

and fats

CANDELILLA WAX. A yellowish amorphous wax obtained by hot water

or solvent extraction from the stems of the shrubs Pedilanthus nis and Euphorbia antisyphilitica, growing in the semiarid regions of

pavo-Texas and Mexico The plants grow to a height of 3 to 5 ft (0.9 to 1.5m) and consist of a bundle of stalks without leaves The stems yield3.5 to 5% wax that consists of, unusually for a vegetable wax, about

55% hydrocarbons, principally hentriacontane, and less than 30%

esters The wax has a specific gravity of 0.983, melting point of 153 to158°F (67 to 70°C), iodine value of 37, and saponification value of

45 to 65 The refined grade is purified by remelting and contains notmore than about 1% water It is soluble in turpentine and is used forvarnishes, polishes, and leather finishes; as a substitute for carnaubawax; or to blend with carnauba or beeswax About half the productiongoes into furniture and show polishes, but it does not have the self-polishing characteristics of carnauba wax It is also used in electricalinsulators, candles, and sound records.

CANNEL COAL. A variety of coal having some of the characteristics ofpetroleum, valued chiefly for its quick-firing qualities It consists ofcoallike matter intimately mixed with clay and shale, often contain-ing fossil fishes, and probably derived from vegetable matter in lakes

It is compact in texture, dull black, and breaks along joints, oftenhaving an appearance similar to black shale It burns with a long,luminous, smoky flame, from which it derives its old English name,meaning candle On distillation, cannel coal yields a high proportion

of illuminating gas, up to 16,000 ft3/ton (450 m3/ton), leaving aresidue consisting mostly of ash At low temperatures it yields a highpercentage of tar oils The proportion of volatile matter may be ashigh as 70% It is found in Great Britain and in Kentucky, Ohio, and

Indiana Cannel coal from Scotland was originally called parrot

coal, and boghead coal was a streaky variety.

CARBOHYDRATES. The most abundant class of organic compounds,constituting about three-fourths of the dry weight of the plant world.They are distinguished by the fact that they contain the elements car-bon, hydrogen, and oxygen, and no others Many chemical com-pounds, such as alcohols and aldehydes, also have these elements

only, but the term carbohydrate refers only to the starches, sugars,

and cellulose, which are more properly called saccharides Their

properties vary enormously Sugars are soluble, crystalline, andsweet; starches form pastes and are colloidal; celluloses are insoluble.They are best known for their use as foodstuffs, as carbohydratescompose more than 50% of all U.S food, but they are also used inmany industrial processes The digestible carbohydrates are the sug-ars and the starches The indigestible carbohydrates are cellulose andhemicellulose, which form the chief constituents of woods, stalks, andleaves of plants, the outer covering of seeds, and the walls of plantcells enclosing the water, starches, and other substances of the plants.Much cellulose is eaten as food, especially in the leaves of vegetablesand in bran; but it serves as bulk rather than as food and is benefi-cial, if not consumed in quantity The digestible carbohydrates are

classified as single sugars, double sugars, and complex sugars, chemically known as monosaccharides, disaccharides, and poly-

saccharides The single sugars—glucose, fructose, and galactose—

require no digestion and are readily absorbed into the bloodstream.The double sugars—sucrose, maltose, and lactose—must be broken

down by enzymes in the human system Lactose, produced from milk

solids, is a nonhygroscopic powder It is only 16% as sweet as sugarand not as soluble, but it enhances flavor It digests slowly It is used

in infant foods, dairy drinks, and ice cream to improve low-fat ness, in bakery products to decrease sogginess and improve browning,

rich-and as a dispersing agent for high-fat powders Galactose is derived from lactose by hydrolysis Multisugars are mixed sugars with the

different sugars interlocked in the crystals They dissolve rapidly toform clear solutions

The complex sugars are the starches, dextrins, and glycogen Theserequire digestion to the single stage before they can be absorbed inthe system The common starches are in corn, wheat, potatoes, rice,

tapioca, and sago Animal starch is the reverse food of animals stored in the liver and muscles It is glycogen, a sweet derivative of

glycolic acid It is not separated out commercially because it is

hygro-scopic and quickly hydrolyzed Dextran, related to glycogen, is a

polyglucose made up of many molecules of glucose in a long chain It

is used as an extender of blood plasma It can be stored indefinitelyand, unlike plasma, can be sterilized by heat It is produced commer-cially by biotic fermentation of common sucrose sugar

The hemicelluloses are agar-agar, algin, and pectin They differ

chemically from cellulose and expand greatly on absorbing water The

hemicelluloses of wood, called hexosan, consist of the wood sugars, or

hexose, with six carbon atoms, (C6H10O5)n They are used to make manychemicals The water-soluble hemicellulose of Masonite Corp., known as

Masonex in water solution and Masonoid as a powder, is a by-product

of the steam-exploded wood process It is used to replace starch as abinder for foundry cores and for briquetting coal, and for emulsions It

contains 70% wood sugars, 20 resins, and 10 lignin Lichenin, or moss

starch, is a hemicellulose from moss and some seeds.

The pentosans are gums or resins occurring in nutshells, straw,

and the cell membranes of plants They may be classified as

hemi-cellulose and on hydrolysis yield pentose, or pentaglucose, a sugar containing five carbon atoms Pectin is a yellowish, odorless

powder soluble in water and decomposed by alkalies It is produced

by acid extraction from the inner part of the rind of citrus fruitsand from apple pomace In east Africa it is obtained from sisal

waste Flake pectin is more soluble and has a longer shelf life

than the powdered form It is produced from a solution of applepomace containing 5% pectin by drying on steam-heated drums,and the thin film obtained is flaked to 40 mesh Another source is

sugar-beet pulp, which contains 20 lb (9.7 kg) of pectin per ton

(0.91 metric ton)

Pectin has a complex structure, having a lacturonic acid withmethanol in a glucoside chain combination It is used for gelling fruitpreserves, and the gelling strength depends on the size of the mole-cule, the molecular weight varying from 150,000 to 300,000 It is alsoused as a blood coagulant in treating hemorrhage, and for prolongingthe effect of some drugs by retarding their escape through the body.

Sodium pectate is used for creaming rubber latex, and in cosmetics

and printing inks Hemicellulose and pectin are valuable in thehuman system because of their ability to absorb and carry away irri-

tants, but they are not foods in the normal sense of the term Oragen

is a pectin-cellulose complex derived from orange pulp It is used inweight-reduction diets, increasing bulk and retaining moisture, thussuppressing the desire for excess food Each of the saccharides hasdistinctive characteristics of value in the system, but each also inexcess causes detrimental conditions Coating french fries with apectin-based oil-absorbing barrier developed by Hercules Inc., world’slargest pectin supplier, keeps the fries from absorbing oil in cooking,reducing fat content

CARBON. A nonmetallic element, symbol C, existing naturally in eral allotropic forms and in combination as one of the most widely dis-tributed of all the elements It is quadrivalent and has the property offorming chain and ring compounds, and there are more varied and use-ful compounds of carbon than of all other elements Carbon enters intoall organic matter of vegetable and animal life, and the great branch of

sev-organic chemistry is the chemistry of carbon compounds The black

amorphous carbon has a specific gravity of 1.88; the black crystalline

carbon known as graphite has a specific gravity of 2.25; the transparent

crystalline carbon, as in the diamond, has a specific gravity of 3.51

Amorphous carbon is not soluble in any known solvent It is infusible,

but sublimes at 6332°F (3500°C), and is stable and chemically inactive

at ordinary temperatures At high temperatures it burns and absorbsoxygen, forming the simple oxides CO and CO2, the latter being the sta-ble oxide present in the atmosphere and a natural plant food

An amorphous carbon made from polycarbodiimide by NisshinboIndustries of Japan has far greater bending strength than graphitecarbon and amorphous carbon made from phenol It is not attacked

by most chemicals and resists temperatures exceeding 5400°F

(2980°C) An amorphous carbon coating, developed at Argonne

National Laboratories, is extremely hard and, under inert conditions,almost frictionless, having a coefficient of friction of less than 0.001 in

a dry nitrogen atmosphere, which is 20 times less than that of

molybdenum disulfide and far less than Teflon’s 0.04 Peel

strength in 200,000 lb/in2 (1379 MPa) In arid or humid

ments, however, the coefficient of friction rises to 0.02 to 0.07 Also,the coating cannot be used at temperatures exceeding 392°F (200°C),such temperature causing severe wear The coating, deposited byroom-temperature chemical vapor deposition, can be applied to alu-minum, steel, ceramics, and various plastics Hydrogenated amor-phous carbon coating doped with nitrogen, applied by the Actisprocess of Sidel (France), increases the oxygen-barrier quality of

polyethylene terephthalate beer bottles by a factor of 30 compared

with single-layer bottles A diamondlike carbon (DLC) coating,

developed by Nissei ASB (Japan), is also a barrier coating for PETbeer bottles and other applications, including other drinks, vitamins,and cosmetics

Carbon dissolves easily in some molten metals, notably iron, ing great influence on them Steel, with small amounts of chemicallycombined carbon, and cast iron, with both combined carbon and

exert-graphitic carbon, are examples of this Volatile organic compounds

(VOCs) are carbon compounds, readily passed off by evaporation, thatreact to form ground-level ozone, a primary component of smog Theypertain to many solvents, degreasers, paints, and chemicals, andgreat efforts have been made in recent years to reduce their emission.Carbon occurs as hydrocarbons in petroleum, and as carbohydrates

in coal and plant life, and from these natural basic groupings an nite number of carbon compounds can be made synthetically Carbon,for chemical, metallurgical, or industrial use, is marketed in the form

infi-of compounds in a large number infi-of different grades, sizes, and shapes;

or in master alloys containing high percentages of carbon; or as vated carbons, charcoal, graphite, carbon black, coal-tar carbon,petroleum coke; or as pressed and molded bricks or formed parts with

acti-or without binders acti-or metallic inclusions Natural deposits ofgraphite, coal tar, and petroleum coke are important sources of ele-mental carbon Charcoal and activated carbons are obtained by car-bonizing vegetable or animal matter Many seal applications makeuse of a carbon face because of the material’s lubricity, inertness, andrange of abrasion resistance; soft grades are for contact with soft met-als, more abrasion-resistant grades are for contact with hard metals

or fluids containing dissolved solids

Carbon 13 is one of the isotopes of carbon, used as a tracer in

bio-logic research where its heavy weight makes it easily distinguished

from other carbon Carbon 14, or radioactive carbon, has a longer

life It exists in air, formed by the bombardment of nitrogen by cosmicrays at high altitudes, and enters into the growth of plants The half-life is about 6,000 years It is made from nitrogen in a cyclotron

Carbon fullerenes, such as C60, are a new form of carbon, discovered

in the mid-1980s, with considerable potential in diverse applications

Carbon fibers are made by pyrolysis of organic precursor fibers in

an inert atmosphere Pyrolysis temperatures can range from 2012 to5432°F (1000 to 3000°C); higher process temperatures generally lead

to higher-modulus fibers Only three precursor materials—rayon,

polyacrylonitrile (PAN), and pitch—have achieved significance in

commercial production of carbon fibers The first high-strength andhigh-modulus carbon fibers were based on a rayon precursor Thesefibers were obtained by being stretched to several times their originallength at temperatures above 5072°F (2800°C) The second generation

of carbon fibers is based on a PAN precursor and has achieved marketdominance In their most common form, these carbon fibers have atensile strength ranging from 350,000 to 450,000 lb/in2(2,413 to 3,102MPa), a modulus of 28 106 to 75  106 lb/in2 (193,000 to 517,000MPa), and a shear strength of 13,000 to 17,000 lb/in2(90 to 117 MPa).This last property controls the traverse strength of composite materi-als The high-modulus fibers are highly graphitic in crystalline struc-ture after being processed from PAN at temperatures in excess of3600°F (1982°C) Higher-strength fibers obtained at lower tempera-tures from rayon feature a higher carbon crystalline content Thereare also carbon and graphite fibers of intermediate strength and mod-

ulus The third generation of carbon fibers is based on pitch as a

pre-cursor Ordinary pitch is an isotropic mixture of largely aromaticcompounds Fibers spun from this pitch have little or no preferred ori-entation and hence low strength and modulus Pitch is a very inexpen-sive precursor compared with rayon and PAN High-strength andhigh-modulus carbon fibers are obtained from a pitch that has first

been converted to a mesophase (liquid crystal) These fibers have a

tensile strength of more than 300,000 lb/in2(2,069 MPa) and a Young’smodulus ranging from 55 106to 75  106 lb/in2 (379,000 to 517,000MPa) The average filament diameter of continuous yarn is 0.0003 in(0.008 mm) Pitch-based carbon and graphite fibers are expected to seeessentially the same applications as the more costly PAN- and rayon-derived fibers, e.g., ablative, insulation, and friction materials and in

metals and resin matrixes Thornel, developed by Union Carbide

Corp., is a yarn made from these filaments for high-temperature rics It retains its strength to temperatures above 2800°F (1538°C)

fab-Carbon yarn is 99.5% pure carbon It comes in plies of 2 to 30, with

each ply composed of 720 continuous filaments of 0.0003-in (0.008-mm)diameter Each ply has a breaking load of 2 lb (0.91 kg) The fiber hasthe flexibility of wool and maintains dimensional stability to 5700°F

(3150°C) Thornel radiotranslucent carbon fiber, from Amoco

Polymers, allows electrical conduction while remaining invisible to X-rays, permitting babies’ monitoring equipment to stay intact duringX-rays and MRIs

KIIOOX fiber, from Amoco Performance Products, Inc., is a

pitch-carbon fiber for prepreg used to produce composites for thermal management systems in space satellites Ucar, developed by Union Carbide Corp., is a conductive carbon fabric made from carbon

yarns woven with insulating glass yarns with resistivities from 0.2 to

30 for operating temperatures to 550°F (288°C) Carbon wool, for

filtering and insulation, is composed of pure-carbon fibers made bycarbonizing rayon The fibers, 197 to 1,970
in (5 to 50
m) in diame-ter, are hard and strong and can be made into rope and yarn, or the

mat can be activated for filter use Avceram RS, of FMC Corp., is a

composite rayon-silica fiber made with 40% dissolved sodium silicate

A highly heat-resistant fiber, Avceram CS is woven into fabric and then pyrolyzed to give a porous interlocked mesh of carbon silica

fiber, with a tensile strength of 165,000 lb/in2(1,138 MPa) Dexsan,

of C H Dexter & Sons Co., for filtering hot gases and liquids, is a

carbon filter paper made from carbon fibers pressed into a

paper-like mat, 0.007 to 0.050 in (0.18 to 0.127 mm) thick, and impregnatedwith activated carbon

In a process developed by Mitsubishi Gas Chemical Co (Japan)

naphthalene is used as the feedstock for mesophase pitch, called AR-Resin, to produce carbon fiber Conoco Inc uses a mesophase pitch

to make carbon-fiber mat This pitch has an anisotropic molecularstructure rather than the more amorphous one of the PAN precursor

Carbon brushes for electric motors and generators and carbon electrodes are made of carbon in the form of graphite, petroleum

coke, lampblack, or other nearly pure carbon, sometimes mixed withcopper powder to increase the electrical conductivity, and then pressedinto blocks or shapes and sintered Carbon-graphite brushes contain

no metals but are made from carbon-graphite powder and, after

pressing, are subjected to a temperature of 5000°F (2760°C), whichproduces a harder and denser structure, permitting current densities

up to 125 A /in2 (1,538 A /m2) Carbon brick, used as a lining in the

chemical processing industries, is carbon compressed with a nous binder and then carbonized by sintering If the binder is capable

bitumi-of being completely carbonized, the bricks are impervious and dense

Graphite brick, made in the same manner from graphite, is more

resistant to oxidation than carbon bricks and has a higher thermalconductivity, but it is softer The binder may also be a furfural resin

polymerized in the pores Karbate No 1 is a carbon-base brick, and

Karbate No 2 is a graphite brick Karbate has a crushing strength of

10,500 lb/in2(72 MPa) and a density of 110 to 120 lb/ft3(1,762 to 1,922kg/m3) Impervious carbon is used for lining pumps, for valves, and

for acid-resistant parts It is carbon- or graphite-impregnated with achemically resistant resin and molded to any shape It can be

machined Karbate 21 is a phenolic-impregnated graphite, and

Karbate 22 is a modified phenolic-impregnated graphite Molded

impervious carbon has a specific gravity of 1.77, tensile strength of1,800 lb/in2 (12.4 MPa), and compressive strength of 10,000 lb/in2

(69 MPa) Impervious graphite has a higher tensile strength, 2,500

lb/in2 (17.2 MPa), but a lower compressive strength, 9,000 lb/in2(62 MPa) The thermal conductivity is 8 to 10 times that of stainless

steel Graphitar, of U.S Graphite Co., is a strong, hard carbon molded

from amorphous carbon mixed with other forms of carbon It has highcrushing strength and acid resistance and is used for sealing rings,

chemical pump blades, and piston rings Porous carbon is used for

the filtration of corrosive liquids and gases It consists of uniform ticles of carbon pressed into plates, tubes, or disks without a binder,leaving interconnecting pores of about 0.001 to 0.0075 in (0.025 to0.190 mm) in diameter The porosity of the material is 48%, tensilestrength 150 lb/in2(1 MPa), and compressive strength about 500 lb/in2

par-(3.5 MPa) Porous graphite has graphitic instead of carbon particles,

and is more resistant to oxidation but is lower in strength

Carbon/carbon composites, which comprise carbon fibers in a

carbon matrix, are noted for their heat resistance, high-temperaturestrength, high thermal conductivity, light weight, low thermalexpansivity, and resistance to air/fuel mixtures However, they arecostly to produce Also, they react with oxygen at temperatures

above 800°F (427°C), necessitating oxygen-barrier coatings Silicon

carbide, 0.005 to 0.007 in (0.127 to 0.178 mm) thick, serves as such

a coating for applications in the nose cone and wing leading edges

of the Space Shuttle Other uses include the brakes of large mercial aircraft, clutches and brakes of Formula 1 race cars, androcket nozzles

com-Carbon films, usually made by chemical vapor deposition (CVD)

at 2012°F (1100°C), can strengthen and toughen ceramic-matrix

composites but are not readily adaptable to coating fibers, platelets,

or powder The Japanese have developed what is said to be a moreeconomical method using silicon carbide and other ceramics.Nanometer- to micrometer-thick films are formed on these forms,including silicon carbide single crystals, by treating them with waterunder pressure at 572 to 1472°F (300 to 800°C) This treatment trans-forms the surface layer to carbon

The so-called carbons used for electric-light arc electrodes are

pressed from coal-tar carbon, but are usually mixed with other ments to bring the balance of light rays within the visible spectrum.Solid carbons have limited current-carrying capacity, but when thecarbon has a center of metal compounds such as the fluorides of therare earths, its current capacity is greatly increased It then forms adeep positive crater in front of which is a flame 5 times the brilliance

of that with the low-current arc The sunshine carbon, used in

elec-tric-light carbons to give approximately the same spectrum as light, is molded coal-tar carbon with a core of cerium metals to

sun-introduce more blue into the light Arc carbons are also made to give

other types of light, and to produce special rays for medicinal and

other purposes B carbon, of National Carbon Co., Inc., contains iron

in the core and gives a strong emission of rays from 9,055 to 12,598nin (230 to 320 nm), which are the antirachitic radiations The lightseen by the eye is only one-fourth the total radiation since the strong

rays are invisible C carbon contains iron, nickel, and aluminum in

the core and gives off powerful lower-zone ultraviolet rays It is used

in light therapy and for industrial applications E carbon, to produce penetrating infrared radiation, contains strontium Electrode car-

bon, used for arc furnaces, is molded in various shapes from carbon

paste When calcined from petroleum coke, the electrodes contain only0.2% moisture, 0.25 volatile matter, and 0.3 ash and have a specificgravity of 2.05 The carbon is consumed in the production of light and

of furnace heat For example, from 1,100 to 1,320 lb (500 to 600 kg) ofcarbon is consumed in producing 1 ton (0.91 metric ton) of aluminum

CARBON BLACK. An amorphous powdered carbon resulting from theincomplete combustion of a gas, usually deposited by contact of theflame on a metallic surface, but also made by the incomplete combus-tion of the gas in a chamber The carbon black made by the first

process is called channel black, taking the name from the channel

iron used as the depositing surface The modern method, called the

impingement process, uses many small flames with the fineness of

particle size controlled by flame size The air-to-gas ratio is high, ing oxidized surfaces and acid properties No water is used for cool-ing, keeping the ash content low The supergrade of channel black has

giv-a pgiv-article size giv-as low giv-as 512
in (13
m) giv-and giv-a pH of 3 to 4.2 Cgiv-arbon

black made by other processes is called soft black and is weaker in color strength, not so useful as a pigment Furnace black is made

with a larger flame in a confined chamber with the particles settlingout in cyclone chambers The air-to-gas ratio is low, and water coolingraises the ash content The particle surface is oily, and the pH is high

Black Pearl 3700, 4350, and 4750 are high-purity furnace blacks

from Cabot Corp The 3700, with cleanliness and cable smoothnessand cleanliness similar to acetylene, is intended as an alternative tothe latter for semiconductive cable shields The 4350 and 4750 couldbecome the first furnace blacks used for single-service food packagingbecause of their low polyaromatic-hydrocarbon content and better dis-persion and impact resistance than selective channel blacks approvedfor this application

Carbon black from clean artificial gas is a glossy product with anintense color, but all the commercial carbon black is from natural gas.

To remove H2S, the sour gas is purified and water-scrubbed before

burning Thermotomic black, a grade made by the thermal

decom-position of the gas in the absence of oxygen, is preferred in rubberwhen high loadings are employed because it does not retard the vul-canization; but only a small part of the carbon black is made by thisprocess This thermal process black has large particle size, 5,906
in(150
m), and a pH of 8.5 It gives a coarse oily carbon

The finer grades of channel black are mostly used for color pigment

in paints, polishes, carbon paper, and printing and drawing inks Thelarger use of carbon black is in automotive tires to increase the wearresistance of the rubber The blacker blacks have a finer particle sizethan the grayer blacks, hence have more surface and absorptive capac-ity in compounding with rubber Channel black is valued for rubbercompounding because of its low acidity and low grit content The high

pH of furnace black may cause scorching unless offsetting chemicalsare used, but some furnace blacks are made especially for tire com-pounding In general, the furnace black with particle sizes from 1,100

to 3,350
in (28 to 85
m) and a pH from 8 to 10, and the channelblacks with particle size of about 1,140
in (29
m) and pH of 4.8, are

used for rubber Micronex EPC, an impingement channel black of

Binney & Smith Co., has a particle diameter of 1,140
in (29
m) and

a pH of 4.8, while Thermax MT, a thermal process black of Cancarb

Ltd., has a particle size of 10,800
in (274
m) and a pH of 7

In rubber compounding, the carbon black is evenly dispersed tobecome intimately attached to the rubber molecule The fineness ofthe black determines the tensile strength of the rubber, the structure

of the carbon particle determines the modulus, and the pH mines the cure behavior Furnace blacks have a basic pH which acti-vates the accelerator, and delaying-action chemicals are thus needed,but fine furnace blacks impart abrasion resistance to the rubber.Furnace black made with a confined flame with limited air has a neu-tral surface and a low volatility Fineness is varied by temperature,size of flame, and time Carbonate salts raise the pH Most of thechannel black for rubber compounding is made into dustfree pelletsless than 0.125 in (0.3 cm) in diameter with a density of 20 to 25 lb/ft3(320 to 400 kg/m3) Color-grade black for inks and paints is pro-

deter-duced by the channel process or the impingement process In general,carbon black for reinforcement has small particle size, and the electri-

cally conductive grades, CF carbon black and CC carbon black,

conductive furnace and conductive channel, have large particle sizes.Carbon black from natural gas is produced largely in Louisiana,Texas, and Oklahoma About 35 lb (15.9 kg) of black is available per1,000 ft3(28 m3) of natural gas, but only 2.2 lb (1 kg) is recovered by the

channel process and 10 lb (4.5 kg) by the furnace method By using gasfrom which the natural gasoline has been stripped, and by controlledpreheating and combustion, as much as 27 lb (12.2 kg) can be recovered.

Acetylene black is a carbon black made by heat decomposition of

acetylene It is more graphitic than ordinary carbon black with colloidalparticles linked together in an irregular lattice structure and has highelectrical conductivity and high liquid-absorption capacity Particle size

is intermediate between that of channel black and furnace black, withlow ash content, nonoiliness, and a pH of 6.5 It is valued for use in dry

cells and lubricants Ucet, of Union Carbide Corp., is in the form of

agglomerates of irregular fine crystals The greater surface area giveshigher thermal and electrical conductivity and high liquid absorption

For electrically conductive rubber, the mixing of the black with

the rubber is regulated so that carbon chain connections are not ken Such conductive rubber is used for tabletops, conveyor belts, andcoated filter fabrics to prevent static buildup Carbon blacks are alsomade from liquid hydrocarbons, and from anthracite coal by treat-ment of the coal to liberate hydrogen and carbon monoxide and thenhigh-temperature treatment with chlorine to remove impurities Theblack made from anthracite has an open-pore structure useful forholding gases and liquids

bro-Carbon-black grades are often designated by trade names for

par-ticular uses Kosmovar is a black with a slight bluish top tone

used as a pigment for lacquers The specific gravity is 1.72, and

mesh is 325 Gastex and Pelletex are carbon blacks used for ber compounding Statex is a colloidal furnace black for synthetic rubber compounding Kosmos 60 is a furnace black of high density and structure, while Continex FF is a finely divided furnace black.

rub-Both are used in rubber compounding, the first giving easier sion of the rubber and the second giving better abrasion resistance

extru-Aquablak H, of Binney & Smith Co., is a colloidal water dispersion

of channel black to give a jet-black color Aquablak M is a water

dispersion of furnace black to give a blue-gray tone They are used

as pigments in casein paint, inks, and leather finishes Black

Pearls 3700 is a series of high-purity furnace blacks from Cabot

Corp with far less ash, sulfur, and ion content than conventionalfurnace black Thus it has better electrical performance, melt-flowproperties, and smoothness than acetylene blacks and is a candi-

date for power cable insulation shielding Liquimarl-Black is a

stable colloidal dispersion of pure food-grade carbon black for use incoloring confectionery and for modifying food colors in bakery prod-ucts The National Aeronautics and Space AdministrationPropulsion Laboratories has determined that the addition of

Shawanigen carbon black markedly increases the life of

phous-carbon or graphite anodes in rechargeable lithium-ion trochemical cells.

elec-CARBON DIOXIDE Also called carbonic anhydride, and in its solid state, dry ice A colorless, odorless gas of composition CO2, which liq-uefies at 85°F (65°C) and solidifies at 108.8°F (78.2°C).Release of CO2 into the atmosphere by the burning of fossil fuels is

said to be causing global warming by the process known as the house effect It is recovered primarily as a by-product of the steam re-

green-forming of natural gas to make hydrogen or synthesis gas inpetroleum and fertilizer plants Smaller quantities are obtained bypurifying flue gases generated from burning hydrocarbons or lime,and from distilleries Its biggest uses are captive, as a chemical rawmaterial for making urea and in enhanced oil recovery operations inpetroleum production Merchant CO2 is more than 99.5% pure, withless than 500 ppm (parts per million) of nonvolatile residues In liquidform it is marketed in cylinders and is used in fire extinguishers, inspray painting, in refrigeration, for inert atmospheres, for the manu-

facture of carbonated beverages, and in many industrial processes.

It is also marketed as dry ice, a white, snowlike solid used for

refrig-eration in transporting food products Cardox is a trade name of

Cardox Corp for liquid carbon dioxide in storage units at 30 lb/in2(0.21 MPa) pressure for fire-fighting equipment Other uses includehardening of foundry cores, neutralization of industrial wastes, andproduction of salicylic acid for aspirin Carbon dioxide is a key lasing

gas in carbon dioxide lasers and is also used as a shielding gas in

welding and as a foaming agent in producing plastic foam products It

can behave as a supercritical fluid, in which state it can be used to

foam plastics and extract hazardous substances in waste treatmentprocesses and in soil remediation CO2 is used to wash brownstock inthe pulp and paper industry, thereby sending cleaner pulp on to bleach-ing In cooling systems, it is an alternative to halogenated-carbon

refrigerants CO 2 “snow,” pellets that is, is used to cool freshly laid

eggs, cuts of meat and poultry, and flour in baking Dry ice pellets are

blasted on molds to clean them of plastic residuals Liquid carbon

dioxide is used in SuperFuge, an immersion system by Deflex Corp to

rid products of surface contaminants

CARBON MONOXIDE. CO is a product of incomplete combustion and

is very reactive It is one of the desirable products in synthesis gas formaking chemicals, the synthesis gas made from coal containing atleast 37% CO It is also recovered from top-blown oxygen furnaces insteel mills It reacts with hydrogen to form methanol, which is thencatalyzed by zeolites into gasoline Acetic acid is made by methanol

carbonylation, and acrylic acid results from the reaction of CO, lene, and methanol CO forms a host of neutral, anionic, and cationic

acety-carbonyls, with such metals as iron, cobalt, nickel, molybdenum,

chromium, rhodium, and ruthenium Pressure Chemical Co and

Strem Chemicals Inc make molybdenum carbonyl, chromium

carbonyl, and other complexes for olefin carbonylation and

isomer-ization, and carboxylation reactions Carbon monoxide is an intensepoison when inhaled and is extremely toxic even in the smallamounts from the exhausts of internal-combustion engines

CARBON STEEL The wrought carbon steels covered here are sometimes termed plain carbon steels The old shop names of

machine steel and machinery steel are still used to mean any

eas-ily worked low-carbon steel By definition, plain carbon steels arethose that contain up to about 1% carbon, not more than 1.65 man-ganese, 0.60 silicon, and 0.60 copper, and only residual amounts ofother elements, such as sulfur (0.05% maximum) and phosphorus(0.04% maximum) They are identified by means of a four-digitnumerical system established by the American Iron and SteelInstitute (AISI) The first digit is the number 1 for all carbon steels

A 0 after the 1 indicates nonresulfurized grades, a 1 for the seconddigit indicates resulfurized grades, and 2 for the second digit indi-cates resulfurized and rephosphorized grades The last two digitsgive the nominal (middle of the range) carbon content in hundredths

of a percent For example, for grade 1040, the 40 represents a carbonrange of 0.37 to 0.44% If no prefix letter is included in the designa-tion, the steel was made by the basic open-hearth, basic oxygen, orelectric furnace process The prefix B stands for the acid Bessemerprocess, which is obsolete, and the prefix M designates merchantquality The letter L between the second and third digits identifiesleaded steels, and the suffix H indicates that the steel was produced

to hardenability limits

For all plain carbon steels, carbon is the principal determinant ofmany performance properties Carbon has a strengthening and hard-ening effect At the same time, it lowers ductility, as evidenced by adecrease in elongation and reduction of area In addition, increasingcarbon content decreases machinability and weldability, but improveswear resistance The amount of carbon present also affects physicalproperties and corrosion resistance With an increase in carbon con-tent, thermal and electrical conductivity decline, magnetic permeabil-ity decreases drastically, and corrosion resistance is less

Carbon steels are available in most wrought mill forms, includingbar, sheet, plate, pipe, and tubing Sheet is primarily a low-carbon-steel product, but virtually all grades are available in bar and plate

Plate, usually a low-carbon or medium-carbon product, is used mainly

in the hot-finished condition, although it also can be supplied treated Bar products, such as rounds, squares, hexagonals, and flats(rectangular cross sections), are also mainly low-carbon and medium-carbon products and are supplied hot-rolled and cold-finished Coldfinishing may be by drawing (cold-drawn bars are the most widelyused); turning (machining) and polishing; drawing, grinding, and pol-ishing; or turning, grinding, and polishing Bar products are alsoavailable in various quality designations, such as merchant quality(M), cold-forging quality, cold-heading quality, and several others.Sheet products have quality designations as noted in low-carbonsteels, which follow Plain carbon steels are commonly divided intothree groups, according to carbon content: low carbon, up to 0.30%;medium carbon, 0.31 to 0.55; and high carbon, 0.56 to 1

heat-Low-carbon steels are the grades AISI 1005 to 1030 Sometimes

referred to as mild steels, they are characterized by low strength

and high ductility and are nonhardenable by heat treatment except

by surface-hardening processes Because of their good ductility, carbon steels are readily formed into intricate shapes These steelsare also readily welded without danger of hardening and embrittle-ment in the weld zone Although low-carbon steels cannot be through-hardened, they are frequently surface-hardened by various methods(carburizing, carbonitriding, and cyaniding, for example) which dif-fuse carbon into the surface Upon quenching, a hard, wear-resistantsurface is obtained

low-Low-carbon sheet and strip steels (1008 to 1012) are widely used

in cars, trucks, appliances, and many other applications Hot-rolledproducts are usually produced on continuous hot strip mills Cold-rolledproducts are then made from the hot-rolled products, reducing thick-ness and enhancing surface quality Unless the fully work-hardenedproduct is desired, it is then annealed to improve formability and tem-per-rolled to further enhance surface quality Hot-rolled sheet and strip

and cold-rolled sheet are designated commercial quality (CQ), drawing quality (DQ), drawing quality special killed (DQSK), and structural quality (SQ) The first three designations refer, respectively, to steels of

increasing formability and mechanical property uniformity SQ, whichrefers to steels produced to specified ranges of mechanical propertiesand/or bendability values, do not pertain to cold-rolled strip, which isproduced to several tempers related to hardness and bendability.Typically, the hardness of CQ hot-rolled sheet ranges from Rockwell B(RB) 40 to 75, and tensile properties range from ultimate strengths of40,000 to 68,000 lb/in2 (276 to 469 MPa), yield strengths of 28,000 to48,000 lb/in2 (193 to 331 MPa), and elongations of 14 to 43% For DQhot-rolled sheet: RB 40 to 72; 40,000 to 60,000 lb/in2(276 to 414 MPa);

27,000 to 45,000 lb/in2 (186 to 310 MPa); and 28 to 48%, respectively.For CQ cold-rolled sheet: RB 35 to 60; 42,000 to 57,000 lb/in2 (290 to

393 MPa); 23,000 to 38,000 lb/in2(159 to 262 MPa); and 30 to 45% Andfor DQ cold-rolled sheet: RB 32 to 52; 38,000 to 50,000 lb/in2(262 to 345MPa); 20,000 to 34,000 lb/in2(138 to 234 MPa); and 34 to 46%

Special (modified) low-carbon sheet steels may contain small

amounts of other alloying elements Nitrogen in quantities of 0.010 to0.018% or phosphorus (0.03 to 0.15) permits increasing strength with-out decreasing ductility as much as traditional amounts of carbon andmanganese Thus, their use has increased appreciably in recent years,especially in the auto industry As supplied, these steels have tensileyield strengths of 35,000 to 50,000 lb/in2(241 to 345 MPa) and tensile

elongations of 28 to 32% Nitrogenized steels exhibit substantial

strain aging—to 70,000 lb/in2(483 MPa) or greater—during cold ing Although such strengthening may occur naturally, a brief low-temperature age [15 to 30 min at 350°F (177°C)], such as in autopaint-bake cycles, is sometimes recommended The most formable,

form-however, because of their metallurgical cleanliness, are the

intersti-tial-free steels, typified by Armco’s I-F steel Produced by aluminum

deoxidation and vacuum decarburization deoxidation, the carbon tent is only 0.004 to 0.010% and nitrogen 0.004 or less Columbium(0.08 to 0.12%) or columbium and vanadium serve as carbide andnitride formers The drawability of the steel exceeds that of traditionalDQSK grades, but its tensile yield strength is 2,000 to 8,000 lb/in2 (14

con-to 55 MPa) less The formability of low-carbon sheet steels also can be

enhanced by inclusion-shape control, which was initially

imple-mented for high-strength low-alloy steels This involves small tions of zirconium, titanium, or rare-earth elements and special millpractices to alter the shape of nonmetallic inclusions from stringerlike

addi-to small, dispersed globules The strongest of the sheet steels are

Inland Steel’s low- and medium-carbon MartINsite grades Produced

by rapid water quenching after cold rolling, they provide tensile yieldstrengths of 130,000 to 220,000 lb/in2(896 to 1,517 MPa) but little duc-tility, 4 to 2% elongation, respectively

Low-carbon steels 1018 to 1025 in cold-drawn bar 0.625 to 0.875

in (16 to 22 mm) thick have minimum tensile properties of about70,000 lb/in2 (483 MPa) ultimate strength, 60,000 lb/in2 (413 MPa)yield strength, and 18% elongation Properties decrease somewhatwith increasing section size to, say, 55,000 lb/in2 (379 MPa), 45,000lb/in2 (310 MPa), and 15%, respectively, for 2- to 3-in (50- to 76-mm)cross sections

Medium-carbon steels are the grades AISI 1030 to 1055 They

usually are produced as killed, semikilled, or capped steels and arehardenable by heat treatment However, hardenability is limited to

thin sections or to the thin outer layer on thick parts Medium-carbonsteels in the quenched and tempered condition provide a good balance

of strength and ductility Strength can be further increased by coldwork The highest hardness practical for medium-carbon steels isabout Brinell 550 (Rockwell C 55) Because of the good combination ofproperties, they are the most widely used steels for structural appli-cations, where moderate mechanical properties are required.Quenched and tempered, their tensile strengths range from about75,000 to over 150,000 lb/in2(517 to over 1,034 MPa)

Medium-carbon steel 1035 in cold-drawn bar 0.625 to 0.875 in

(16 to 22 mm) thick has minimum tensile properties of about 85,000lb/in2 (586 MPa) ultimate strength, 75,000 lb/in2 (517 MPa) yieldstrength, and 13% elongation Strength increases and ductilitydecreases with increasing carbon content to, say, 100,000 lb/in2 (689MPa), 90,000 lb/in2 (621 MPa), and 11%, respectively, for medium-

carbon steel 1050 Properties decrease somewhat with increasing

section size to, say, 70,000 lb/in2 (483 MPa), 60,000 lb/in2 (414 MPa),and 10%, respectively, for 1035 steel 2- to 3-in (50- to 76-mm) thick

High-carbon steels are the grades AISI 1060 to 1095 They are,

of course, hardenable with a maximum surface hardness of aboutBrinell 710 (Rockwell C 64) achieved in the 1095 grade These steels

are thus suitable for wear-resistant parts So-called spring steels

are high-carbon steels available in annealed and pretempered stripand wire Besides their spring applications, these steels are used forsuch items as piano wire and saw blades Quenched and tempered,high-carbon steels approach tensile strengths of 200,000 lb/in2(1,378 MPa)

Damascus steels are 1 to 2% carbon steels used for ancient swords

made by blacksmiths using hot and warm forging, which developedlayered patterns The swords were eminent for their strength andsharp cutting edge With carbon in the form of iron carbide, the forgedproducts were free of surface markings With carbon in the form ofspherical carbide, the products could exhibit surface markings So-

called welded damascus steels, also referred to as pattern welded

steels, also exhibit surface markings Superplasticity may be

inher-ent in all of these steels Over the cinher-enturies, dating back to before

Christ, these steels have also been known as bulat steel, Indian

steel, poulad Janherder steel, Toldeo steel, and Wootz steel Free-machining carbon steels are low- and medium-carbon

grades with additions usually of sulfur (0.08 to 0.13%), phorus combinations, and/or lead to improve machinability They

sulfur-phos-are AISI 1108 to 1151 for sulfur grades, and AISI 1211 to 1215 for

phosphorus and sulfur grades The latter may also contain bismuthand be lead-free Tin has also been used to replace lead The pres-